Sexual selection— nesting of birds. 233 



find colouring matter on the eggs, as amongst the 

 Accipitres, the Passeres, the Charadrnformes, Ralli- 

 formes, and GalHformes. By far the greater number 

 of birds that lay white eggs, in holes, are confined to 

 the Picarian forms ; and of those which lay white 

 eggs in open nests, the Humming-Birds belong to 

 that order, whilst the Pigeons and the Owls show 

 many important affinities with it. 



I now arrive at perhaps the most important if 

 least satisfactory part of Mr. Allen's criticism, viz. 

 that which deals wdth the mental powers of birds. 

 If, as Mr. Allen suggests, we define Instinct as 

 inherited habit, I venture to assert that it is not 

 sufficient to explain the phenomenon of a young 

 bird building its first nest. It implies that a young 

 bird, hatched even in an alien nest, would be able 

 to set to work and build a nest typical of the archi- 

 tecture of its species; it implies that that bird is 

 born with a faculty for performing a most complex 

 action ; an amount of precocity which is far more 

 astounding than any powers of imitation and 

 memory that I have ascribed to birds. Mr. Allen 

 cannot produce a scintilla of proof for his assertions 

 — his Inherited Habit is even more of an hypothesis 

 than that of Memory and Imitation. As I said 

 before, it seems monstrously unfair to expect to find 



